Broad band transmission system

• US 5,768,279 A
• Filed: 01/25/1994
• Issued: 06/16/1998
• Est. Priority Date: 01/25/1994
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Barn, Belwinder S., Kothary, Piyush Bhupatrai, Look, Christopher Michael, Geofroy, Joe
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): RAO, SEEMA SRINIVAS
• Application Number:
  US08/186,677
• Time in Patent Office: 1,603 Days
• Field of Search: 370/30, 370/69.1, 370/71, 370/73, 370/76, 370/485-487, 370/496, 455/5.1, 455/3.1, 455/4.1, 455/4.2, 455/6.1, 455/6.2, 359/124, 359/125, 359/127, 348/7, 348/10, 348/12, 348/13, 348/14, 379/93.01
• US Class Current: 370/486
• CPC Class Codes: H04B 2203/542 using zero crossing information
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 3/38 for signals in two different frequency ranges transmitted in opposite directions over the same transmission path
• CPC Class Codes: H04H 2201/70 characterised in that receivers can be addressed
• CPC Class Codes: H04H 60/94 Telephonic networks for accessing the Internet H04H60/84
• CPC Class Codes: H04M 11/00 Telephonic communication systems specially adapted for combination with other electrical systems
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A broad band broadcasting transmission system for sending broad band downstream data and telephone signals from a central office to a number subscriber set top terminal. Each frame of data is marked to indicate the set top terminals it is to be received by. A downstream light fiber is located between the head office and a curbside box. A transmitter transmits the frames along a light fiber to a SAC box. A converter converts the light signals from the light fiber to electrical signals. A distribution line coupled to the curbside box carries the electrical signals to a plurality of drop line twisted pair conductors connected to the distribution line. The drop lines are coupled via a residential units to the set top terminals. The downstream data is transmitted in a single broad frequency band in a frequency range starting sufficiently greater than zero so that distinct frequency bands are available between zero and the starting frequency for the transmission of ordinary telephone service and upstream signals from the set top terminals to the central office.

Claims

1. A digital broad band transmission system for sending downstream broad band data and telephone signals from a central office to a number of subscriber set top terminals and to carry upstream control signals and telephone signals from each set top terminal to the central office, the digital broad band transmission system comprising:

(a) a marking circuit in the central office operative to mark each frame of data to indicate the set top terminals it is to be received by;

(b) a downstream and upstream optical fiber between the central office and a telephone distribution box proximate a plurality of said set top terminals, said downstream optical fiber coupled to said marking circuit;

(c) a telephone signal and data transmitter located in the central office and coupled to said downstream optical fiber and operative to transmit said frames of data and telephone signals along said downstream optical fiber to said telephone distribution box and for receiving upstream telephone and control light signals transmitted from said telephone distribution box along the upstream optical fiber to the central office;

(d) a control signal receiver in said central office coupled to the upstream optical fiber;

(e) an opto-electric converter located in said telephone distribution box and coupled to said downstream optical fiber so as to convert the light signals from said downstream optical fiber to electrical signals and coupled to said upstream optical fiber so as to convert electrical signals from the set top terminal to upstream light signals;

(f) a plurality of telephone drop lines coupled to said telephone distribution box at one end and coupled at another end thereof to respective ones of said plurality of set top terminals, each telephone drop line made up of one or more twisted pairs of conductors, said telephone drop lines operative to conduct said downstream electrical signals to said set top terminals;

(g) a telephone and control signal transmitter in said set top terminal operative to transmit telephone and control signals along said telephone drop lines to said to opto-electric converter for conversion to upstream telephone and control light signals;

wherein said downstream data is broadcast on ones of said twisted pairs in a single broad frequency band in a frequency range starting above a data frequency threshold of 1 megahertz, telephone signals are transmitted from the central office via said telephone distribution box to the set top terminals and from the set top terminals to the central office via said telephone distribution box in a distinct telephone signal frequency band below the data frequency threshold, and upstream control signals are transmitted from the set top terminals via said telephone distribution box to the central office, in a distinct control signal frequency band above said telephone signal frequency band, the control signal frequency band having an upper limit no greater than the data frequency threshold, and

wherein the telephone signal and data transmitter and said telephone and control signal transmitter each output signals that are shaped so that a power versus frequency curve is weighted towards the lower frequencies and power drops to zero at zero frequency.

2. A system according to claim 1, wherein said set top terminals each have a control signal generator for generating control signals in response to subscriber input so as to control the data a subscriber receives.

3. A system according to claim 1, wherein the data, control and telephone signals each have an equal positive and negative going portions so that the average DC level of the signal is zero.

4. A system according to claim 1, wherein at least one of said telephone drop lines is a twisted pair coupled to a subscriber residence coaxial cable installation.

5. A system according to claim 1, wherein said frames are SONET.

6. A system according to claim 1, including a network interface device at each residence for terminating an associated drop line.

7. A system according to claim 1, wherein said single broad frequency band has an upper limit of about 35 megahertz.

12. A system according to claim 7, wherein said single broad frequency band has an upper limit of about 35 megahertz.

13. A system according to claim 7, wherein said broad band distribution line includes a second upstream optical fiber and a second downstream optical fiber.

8. A digital broad band transmission system for sending downstream broad band information in the form of frames of data and telephone signals from a central office to a number of subscriber set top terminals and to carry upstream control signals and telephone signals from each set top terminal to the central office, the digital broad band transmission system comprising:

(a) a marking circuit in said central office for marking each of said frames of data to indicate the set top terminals it is to be received by;

(b) a downstream and an upstream optical fiber between the central office and a service area box proximate a plurality of said set top terminals, said downstream optical fiber coupled to said marking circuit;

(c) a telephone signal and data transmitter in said central office for transmitting data and telephone signals along said downstream optical fiber to said service area box;

(d) an opto-electrical transceiver located in said service area box coupled to said upstream and downstream optical fibers for converting the light signals from said downstream optical fiber to electrical signals and for converting the electrical signals from said set top terminal to light signals for transmission along said upstream optical fiber;

(e) a distribution line coupled to said service area box at one end and to a plurality of curbside boxes located at spaced apart distances from one another;

(f) a plurality of telephone drop lines coupled to said curbside boxes at one end and coupled at another end thereof to respective ones of said set top terminals, each telephone drop line made up of one or more twisted pairs of conductors;

(g) means for transmitting said frames of data to said twisted pair conductors of said drop lines; and

wherein said downstream data is broadcast on ones of said twisted pairs in a single broad frequency band in a frequency range starting above a data frequency threshold of about 1 megahertz and telephone signals are transmitted between the central office and the set top terminals in a distinct telephone signal frequency band (POTS) below the data frequency threshold, and upstream control signals are transmitted from the set top terminals to the central office, in a distinct control signal frequency band above said POTS frequency band, the control signal frequency band having an upper limit no greater than the data frequency threshold, and

wherein the telephone signal and data transmitter and said telephone and control signal transmitter each output signals that are shaped so that the power versus frequency curve is weighted towards the lower frequencies and the power drops to zero at zero frequency.

9. A system according to claim 8, including a data transmitter located in each set top terminal operative to transmit data from each set top terminal to the central office along said telephone drop lines, said distribution line and said upstream optical fiber so that a subscriber may, control the data he receives.

10. A system according to claim 8, wherein at least one of said telephone drop lines is a twisted pair coupled to a subscriber residence coaxial cable installation.

11. A system according to claim 8, including a network interface device at each subscriber residence for terminating an associated telephone drop line.

14. A digital broad band transmission method for delivering from a central office downstream broad band data and telephone signals to a number of subscriber set top terminals and to carry upstream telephone and control signals from each set top terminal to the central office, said downstream broad band data signals including a plurality of frames of data, the method comprising the steps of:

(a) marking each frame of data to indicate the set top terminal or terminals it is Lo be received by;

(b) transmitting said frames of data and downstream telephone signals along an optical fiber to a service area box proximate a plurality of said subscriber set top terminals;

(c) converting the frames of data and downstream telephone signals from light signals to electrical signals;

(d) transmitting the electrical signals along a number of telephone drop lines wherein each telephone drop line is made up of at least one twisted pair of conductors and terminates at a subscriber location;

(e) transmitting upstream telephone signals and subscriber generated control signals from said set top terminals to said central office;

wherein the frames of data are transmitted on ones of said twisted pairs in a single broad frequency band above a data frequency threshold of 1 megahertz, the upstream and downstream telephone signals are transmitted in a second frequency band below said data frequency threshold, and the control signals are transmitted in a third frequency band below said data frequency threshold;

and wherein the downstream and upstream telephone signals, downstream broad band data signals and control signals are shaped so that a power versus frequency curve is weighted towards lower frequencies and power drops to zero at zero frequency.

15. A method according to claim 14, a control signal generator in each set top terminal operative to generate and transmit, in response to subscriber input, control signals to the central office so that a subscriber may control the data he receives.

16. A method according to claim 14, wherein the data, control and telephone signals each positive going portions and negative going portions with the area of the positive going portions equal to that of the negative going portions.

17. A method according to claim 14, wherein said single broad frequency band has an upper limit of about 35 megahertz.

18. A method of digital broad band transmission for use with a telephone system having a central office, a plurality of telephone curbside boxes and a number of set top terminals, said telephone curbside boxes coupled to said central office by at least one transmission line for upstream and downstream communication, each telephone curbside box coupled to at least one of said set top terminals by a telephone drop line having one or more twisted pairs of conductors, the method comprising the steps of:

(a) transmitting frames of data and downstream telephone signals from the central office to ones of said set top terminals via the transmission line, ones of the telephone curbside boxes and ones of the telephone drop lines;

(b) transmitting upstream telephone signals and control signals from the set top terminals along the telephone drop lines to the telephone curbside boxes, and from the telephone curbside boxes to the central office via the transmission line;

wherein the frames of data are transmitted on ones of said twisted pairs in a single broad frequency band above a data frequency threshold of about 1 megahertz, the upstream and downstream telephone signals are transmitted in a second frequency band below said data frequency threshold, and control signals are transmitted in a third frequency band below the data frequency threshold;

and wherein the upstream and downstream telephone signals, said frames of data and the control signals are shaped so that a power versus frequency curve is weighted towards lower frequencies and power drops to zero at zero frequency.

19. A method according to claim 18, wherein the telephone signals occupy a portion of the power versus frequency spectrum from DC up to an upper limit which is below the frequency of the control signal frequency band.

20. A method according to claim 18, including marking each frame of data in the central office with a destination address prior to transmission to said set top terminals.

21. A method according to claim 18, wherein said transmission line is a fiber optic cable having upstream and downstream fibers.

22. A method according to claim 18, including generating and transmitting control signals from the set top terminals to the central office in response to subscriber input so as to control the data a subscriber receives.

23. A method according to claim 18, wherein said single broad frequency band has an upper limit of about 35 megahertz.

24. A method according to claim 18, including generating equal positive and negative going portions for the data, control and telephone signals so that average DC level is zero.

25. A method according to claim 18, wherein said frames of data are SONET frames.

26. A digital broad band transmission system for sending downstream data and telephone signals from a central office to a number of subscriber set top terminals and to carry upstream control signals and telephone signals from each set top terminal to the central office, the digital broad band transmission system comprising:

(a) at least one broad band distribution line coupled to the central office;

(b) a telephone signal and data transmitter located in the central office operative to transmit said downstream data and telephone signals along said broad band distribution line;

(c) a plurality of telephone drop lines, each telephone drop line having a number of twisted pairs of conductors, each twisted pair of conductors coupled to one of said set top terminals;

(d) a telephone distribution box, coupled to said broad band distribution line and to said telephone drop lines, said telephone distribution box operative to;

(i) receive downstream data and telephone signals from said central office;

(ii) transmit downstream data and telephone signals received from the central office to said set top terminals;

(iii) receive control signals and upstream telephone signals from said set top terminals via corresponding twisted pairs; and

(iv) transmit control signals and upstream telephone signals received in (d) (iii) to said central office via said broad band distribution line;

(e) a telephone and control signal transmitter located in each set top terminal operative to transmit said control signals and upstream telephone signals from the set top terminals to said telephone distribution box for transmission to the central office;

wherein said downstream data signals are transmitted in a single broad frequency band above a data frequency threshold of about 1 megahertz, upstream and downstream telephone signals are transmitted in a second frequency band below the single broad frequency band and the control signals are transmitted in a third frequency band below the data frequency threshold;

and wherein the upstream and downstream telephone signals, control signals, and downstream data signals are shaped so that a power versus frequency curve is weighted towards lower frequencies and power drops to zero at zero frequency.

27. A system according to claim 26, wherein said downstream data signals are transmitted in frames of data and wherein the system includes:

a marking circuit in the central office operative to mark each frame of data in the central office with a destination address to indicate the set top terminal it is to be received by.

28. A system according to claim 26, wherein the telephone signals occupy a portion of the power versus frequency spectrum from DC up to an upper limit which is below the frequency of the control signal frequency band.

29. A method according to claim 26, wherein said broad band distribution line includes an upstream optical fiber and a downstream optical fiber.

30. A system according to claim 26, wherein each set top terminal includes a control signal generator for generating and transmitting control signals from the set top terminals to the central office in response to subscriber input so as to control the data a subscriber receives.

31. A system according to claim 26, wherein said single broad frequency band has an upper limit of about 35 megahertz.

32. A system according to claim 26, wherein the data, control and telephone signals each have equal positive and negative going portions so that an average DC level for the signals is zero.

33. A system according to claim 26, wherein said downstream data signals are transmitted in SONET frames.

34. A system according to claim 26, wherein said broad band distribution line includes an upstream optical fiber and a downstream optical fiber and wherein said telephone distribution box includes means for converting the downstream data and telephone signals from the downstream optical fiber to electrical signals for transmission along the telephone drop lines and for converting the upstream telephone and control signals from the telephone drop lines to light signals for transmission along the upstream optical fiber.

35. A system according to claim 34, wherein at least one of said telephone drop lines includes a twisted pair coupled to a subscriber residence coaxial cable installation.

36. A system according to claim 34, wherein at least one of said telephone drop lines includes a fiber optic cable having an upstream and downstream fiber.

37. A system according to claim 34, including a network interface device at each residence for terminating an associated telephone drop line.